Nowadays, holographic displaying technologies have been developed. The term “holographic” may be understood as displaying objects or frames in a three-dimensional (3D) form (i.e., presenting all frames at all view angles of an object). The holographic imaging technologies comprise recording and reproducing images of all frames at all view angles of an object by means of a special technical means so that a visual effect totally the same as the real-world scene is perceived by human eyes.
In the prior art, holographic images can be provided by 3D displaying technologies, and such displaying technologies are being applied increasingly widely. These displaying technologies are implemented not only in the field of computer graphics but also in other different circumstances and technologies. In terms of the 3D displaying technologies, the user usually has to wear a headpiece, a pair of special glasses or the like to transform a planar image into a virtual 3D image. However, this is implemented on an individual basis and is troublesome for the user: for the user who wears a headpiece, a pair of special glasses or the like, the 3D image can only be displayed to the device of the very user alone.
Although these technologies are generally successful, they have not been widely accepted because viewers usually do not like wearing something in front of the eyes. Furthermore, it is impossible for these technologies to project a 3D image to one or more passersby, a group of partners or all audiences simultaneously. Accordingly, it will be very favorable to provide a solution capable of satisfying such a need of viewing a 3D image simultaneously so that a uniquely customized automatic 3D image can be presented to each of a plurality of viewers (i.e., the image seen by each of the viewers is completely different from those seen by any other viewers) who are located in a same viewing environment and who can move freely.